High-voltage terminal connector



Patented May 19, 1953 UNITED STATES PTENT OFFICE HIGH-VGLTAGE TERMINALCfINNICTORV Frederick G. Street, Jrr, Nevv'York; N. Y.

Application August 9, 1949, Serial No. 109,269

Claims.

.This invention relates to high voltage devices and more particularly itrelates .to sealed connector terminals.

A principal object of the invention is to Vprovide an improved sealedbut detachable terminal connector for electrical devices, whereby thelikelihood of voltageibreakdown at the region of the terminal connectionis greatly reduced.

Another principal object is to-increase-the safety factor of highvoltage apparatus by employing a sealed-in joint between a circuitlead-in or supply wire and a. corresponding connectionjoint Within Vtheapparatus; the joint not only being sealed against physical contact butalso being protected against mechanical injury-and against voltagebreakdown by moisture absorption.

One ofthe features of the invention is a connectionjoint for electricalapparatus wherein the overall length of the. apparatusk and itsterminals is greatly reduced since the usual long stand-off insulatorsare completely avoided.

Another feature relates to a connection joint of thekind wherein theactual connection-.between the lead-in or cable wire Yand the contactpoint or lug which forms part of the apparatus, i is located within avsealed chamber: which is YArecessed, at least in part, below the wall ofthe cas'- ing which houses the apparatus, and wherein a novelarrangement of deformable Asealingrings is provided.

i `Anotherfeature relates to an improved detachable connectorfor highvoltage devices, wherein the actual connection joint is sea'l'edwithinanindividual cliainberby special vremovable sealing means to render thesaid-chamber immune' t0 voltagebrealidown inthe presence-of highv hu#midity or ambient moisture conditions.

A further feature relates to an' improvedv detachable connectorA forhigh voltage devices, wherein the actual connection joint is immersed inan individual chamber v'arranged to be 'assembled through the wall ofthe metal enclosing housing of the device, in conjunction with anovelsealing arrangement and assembly which also protects the said chamberfrom mechanicalI in- Jury.

yA further feature relates to a novel arrangement of rubber-like orplasticfsealing rings lwhich are arranged in spaced pairs to reduce thelikeli- Ihood of excessive moisture-absorption at the critical voltagebreakdown points.

A still further feature relates Ato the novel'organization, arrangementand relative location and interconnection of parts which cooperate toprovide animproved and safe terminal connector for high voltage electricapparatus generally.

Other. Vfeatures and advantages not particu larl'y enumerated, will beapparent after a consideration of the following detailed descriptionsandthe appended claims.

The invention is in the nature of an improvement on theflind ofsealed-in connector terminal disclosed in my prior application SerialiNo. 84,301, filed March 30, 1949, now abandoned.

In` the drawing which shows, byway of eX- ample, 'one .preferred mannerof practising the invention,

`Fig. l is a top-plan view of my improved sealed connector joint.

Fig. 2 is a section taken alongv the line 2 2' of Fig. l but inmagnified form. 'Referring to the drawing, the numeral l represents themetallic enclosing casing yof any welllinownelectricaldevice suchiorexample as a high voltage transformer. 4The numeral 2 represents oneoi the insulated lead-.in -wires or circuit conductors havingfany knownelectrical insulatingl sheath. 3, the wire being arranged for electricalconnection to an appropriate point vwithin the device. Heretofore, orderto reduce .the chances of voltage breakdown between.v the wire 2 andcasing, t, it has been the customary .practice to employstand-oftinsulatorsof porcelain or the like. These stand-'ofi insulatorsgreatly increase the -over-all heighteor length of .theapparatus, andlthe vactual .connection joint isexternal to the apparatus and isusuallyopen tothe airy Because v.of this-external projection, .these priorjoints are liable to mechanical breakage. In my prior .applicationSerial No. 84,301,..now abandoned. I- `Ihavewdevised an` `arrangementwhereinl the connector` jointis located within a sealed glass l or.vitreous chambery which is .supported from the. casing wall, and Vwhichis located partly or entirely within said casing..` v-l-Iowever, Ihaverfoundy that yWh-ilenthisprior joint issatisfactorynndermanyconditionsof use, it is subiectfto the-breakage ofthe glass or ceramichousing .when -therprojecting portion or itsfastening nut. issubjected tomechanical` shock.-A Furthermore, .thesealing ot the said glassvor ceramic chambery is effected by a--singledeformable rubber or rubberelike ring lsuclm'ieoprene. -I have foundthatnndenexcessive humidity or ambient moisture conditions, this rubberor-rubber-like sealingiring., overan extended periodofttime, soaks up'enough moisture i to.. lowermthe voltage. breakdown limitfor the joint.The present invention overcomes these 'and other difficulties of thesaid prior sealed joint` 'The actualioint llietween the supply orcircuit 4wire Z and the'contac't lug or terminal 4 is located within amember 5 which may be of insulating plastic, glass or ceramic having theconnector lug or terminal I permanently sealed through the bottom endthereof. The lug 4 is connected to the appropriate conductor 6 of thedevice, for example a transformer winding (not shown) housed within thecasing I. It will be understood of course that while one particular kindof connector lug is shown, any other well-known form of connector lugmay be employed. Member 5 is formed with an integral sealing shoulder 'Iwhich extends completely around the external periphery thereof, and theupper end of member 5 has a smooth flat face arranged to seat against anannular ring 8 of a moisture-proof or non-moisture absorbent plastic. Ihave found that the best results are obtained when this plastic is ofthe types known in the trade as Kel-F (polytrifluorochloroethylene) ornylon It will be observed that the annular opening of ring 8 is oflarger diameter than the diameter of the insulating sheath 3.

Surrounding the member 5, and arranged to be clamped or squeezed against.the lower and upper sides of shoulder 1, are a pair of deformablesealing rings 3, IIJ, of rubber or rubber-like material such asneoprene. The sealing pressure between ring Il and shoulder 1 iseffected by a brass or other metal sleeve II whose lower end has aninwardly curved lip or ange I2. Member II is externally threaded intothe internally threaded bottom I3 of a metal member Iii. Member IIIpasses through the corresponding circular opening in the top wall ofcasing I and has a flat annular flange I5 which is to be brazed,soldered or otherwise permanently sealed or integrally united to thecasing top, as indicated by the numeral I 3. Likewise the threaded jointbetween members I I and I4 is permanently sealed by a brazed, sweated orsilver-soldered joint I1. In effect therefore, member II is rigidlyattached to casing I. The sealing ring II) is clamped against shoulder'I by a metal sleeve or collar I3 which is of slightly larger internaldiameter than the outside diameter of member 5. The upper end of memberII is internally threaded to receive a lock nut or bushing I9 having aslot 20 to receive a suitable fastening tool. Thus by turning the memberI3., the rings 3 and I0 are deformed to completely seal the spacebetween shoulder 'I and member I I. It will be observed however, that anannular gap 2| is left between the rings 9 and IIJ. I have found thatthis gap is of the greatest importance in protecting the space withincasing I sealed against moisture. Furthermore, the use of two separateand spaced rubber rings lo cated as shown, protects the member 5 frommechanical shock and breakage as will be described hereinbelow.

In order to permit Aconductor 2 to be detachably secured to lug 4 whileat the same time completely sealing the chamber 22, a second sealing andfastening assembly is provided. This latter assembly comprises a metalor insulating washer 23 having an inclined inner wall 24. The lower fiatface of washer 23 seats against the abovementioned special plasticwasher 8. Located in the space between washer 23 and the sheath 3 of thesupply wire is a sealing ring 25 which may be of the same material asrings 9 and I Il. The cross-section of ring 25 may be circular so thatwhen it is subjectedto clamping pressure, as will be described, it isannularly deformed to substantially the shape shown in Fig..2, so as toform a moisture-proof seal and at the Sametime to. form .4 a rigid gripbetween the inclined face 24 and the sheath 3. In fact by increasing theclamping pressure, ring 25 can somewhat bite into or inwardly deform thesurface of the sheath 3 as shown.

Seated against the upper flat face of Washer 23 is another plasticwasher 26 having an annular opening of about the same size as theopening in Washer 8 so as to completely clear the sheath 3. Threaded onto the external face of member II is a metal bushing cap 27 having aprojecting head 28. The internal wall of bushing 21 is undercut orrecessed to accommodate the parts 8, 23, 26,- and also to accommodatethe retaining metal spring ring 23 whose purpose will be describedhereinbelow. The flat underface 30 of head 23 is arranged to seatagainst the sealing washer 25 so as to transmit clamping or sealingpressure to the parts located between the flat upper end of member 5 andthe said flat face 30.

The bushing 27 has an enlarged central openingy 3|, the inner wall ofwhich is of somewhat rounded V-shape cross-section to provide aninclined clamping surface 32, and located between the surface 32, thesheath 3 and the washer 26 is another sealing ring 33 preferably,although not necessarily, of the same material as ring 25. It will beseen, therefore, that as the bushing 21 is turned to tighten it, thering 25 is clamped against the sheath 3, and because of the inclinedclamping face 24, this ring is spread out somewhat horizontally toincrease the sealing surface between the washer 26 and the said inclinedsurface 24. Likewise, the ring 33 is subjected to clamping pressurebetween the inclined face 32 and the washer 2B.

I have found that by using two separate deformable sealing rings 25 and33 with an intervening non-absorbent and non-porous washer 26, thechances of moisture entering the chamber 22 are greatly reduced. Thewasher 26 acts as a barrier against the sponge-like transmission ofmoisture between the ring 33 and the ring 25 into chamber 22, whichwould otherwise take place if the two sealing rings were in actualcontact, or if only a single ring were used. Likewise, by providing thegap 2I above described between the rings 3 and Ill, the chances ofmoisture absorbed by one ring and being transmitted or conducted to theother ring, is substantially eliminated. If desired, an additionalsealing gasket 34 may be located between the flat lower lip of bushing27 and the inner flat face of ilange I3. As above-mentioned, a springretaining ring 29 is provided. The purpose of this ring is merely toretain the parts 8, 23, 25, 26, 33, in their assembled position in thebushing 27 before the latter is threaded on t0 the member I I.

It is believed that the manner of assembly of the parts will be clearfrom the foregoing description. However, the following is a resume ofthe steps in the assembly. The member III is threaded and brazed orsilver-soldered to the member II. 'I'he sealing ring 9 is then droppedinto place resting against the shoulder I2. The member 5 carrying theterminal f3 is then dropped into place so that the shoulder 'I engagesthe ring 3. Next the ring I Il is dropped into place against shoulderThe metal collar I8 is then dropped on top of the ring I and thethreaded fastening ring IS is tightened to clamp the member 5 centrallyin position while at the same time deforming the sealing rings 3 and Illas above described. If the optional sealing gasket 34 is to be used, itis then dropped into place resting on the flangel I' i3. The next'stepi'stor invert: the? bushingfZJi tromfthe positlonzshownin'iig-L,thenito' drop the sealing ring 33, washer'ilrsealingring l5;y clampingwasherzisandzwsheri lyinirsuperposed: relation. 1:These can: #their .beiheld inv their' inverted;4 assembledI position by a: suitable-splitaretainer vringr. "This'fassembly #can then be inverted to thefvertical position1 shown in Fig; 2,' and4 it' can: be `threadedzontdtheimember H1 as above described. f'. Arterfrsodermg'parts li' andtirand 'before tighteningupthebushing 221,. the *conductor ZJ'Wi-thlts'rsheathz'iisrpassed through the f assemblyf: and `ther-:conductor-2` isv plugged'finto 'orfotherwise .united-vtothe flug? L WhenV thepartsA 'halve been thus assembled; the? bushing 2li is`tightenedmntilrthe requirew clamping pressure is; transmittedtofthefnariofusi sealing rinesf and washers.

`Itxfhas beenfoundrthatwby fusing the duplex spaced sealing: ringseitherv witlrvanintervening gapsuch asrgap '2.13.01'. with. a,non-porous plastic Washerrs, the desired? clamping nresrmrel can betransmitted -soV as to: eileettvelyigriprthe `slrnathecl conductorZfwhile atfthe. same/time '.efiectively'hermeticallysealingthetcontentsptcasing i and the chamberzzagainstzingress on moisture. '-It will be understood "oflfcourse,Vthat.theacasing l, ifV desired.: can; befprovide'dwith. a filling ci ahigh voltageoilor jel}y,. andilikewfise .the cham.-

voltage oil or yj elly asis Wellknownxinzthe high voltagetransformerart.

. Itrwilly be observed; frorn'thel foregoing -disclosure that lbyreasonof... the'v improved sealing arrangements described; L should for;A anyreasonthe sealing assemblyivonrprisingfthe elements 8,. 23, 25, 26, 33,`be removedorbecome loose, that would not result in anyl deteriorationof the hermetic sealing o`:.the .contents creasing t.

While in the. foregoing description vthe various sealing rings orwashers have been referred to as of rubber-like characteristic; it willbe understood that this is done in a genericsense to coverany-deformable sealing material which has the characteristic ofbeing'deformable-underpressure so as to `spread out radially toeffectthefdesir'ed hermetic' sealing contact with the adjacent' parts, forexample asaillustrationsf'ot-.such materials may be mentioned,"Kel-F-polytriuorochloroethylene, n3/lon, neoprene or even a' deformablesoft metal or'alloy, the' essential features being that the sealingmaterial has the desired deformability as well as the characteristic ofwithstanding the various conditions including the temperature conditionsand moisture conditions under which the device is to be used.

While one particular embodiment has been described herein, it will beunderstood that various changes and modifications may be made thereinwithout departing from the spirit and scope of the invention. Thus, ifdesired, the parts Il and I4 can be made as a single piece, and themember !4 can be internally threaded to receive a corresponding externalthread on member 21 instead of threading member 21 on to member H asshown.

What is claimed is:

l. In combination, a metal housing for a high voltage electrical device,an opening in a wall of said housing through which an insulationsheathedconductor is to pass, metallic means rigidly united to said wall aroundsaid opening and extending interiorly of said casing and having acircular opening with a shouldered ange, a cup-like insulating memberhaving an integral 6 peripheral. Iv shouldergfsai .member .being rclosed at: yione-fend. vand `being. .supported .withinixsaidv casingandwith. its :otheifA end op'enand facing the ffexterior Avof: said.casingr a; rstrsealingiring locatedl vbetween said; fiangef. f andsalidf shoulder, another: sealing ringfalso; engaging saidy shoulderbut/.out ofrmoisture conducting'Contactl with the. rst ring; meanstoclamp; said flange. said shoulder :andssaidiringstogether as a unit,separately removablemearwiforsealing the open. end of. said cup-like.Vmember` and-for gripping said; sheathed conductor; said removable-meanscomprising an annular bushing Einy threaded engagement f with.

said :first-mentioned' metallic: means, said` bushing: having arclampingsurface' inclined down.- wardly.andxoutwardlyirom said sheathedccnductor. a. non-'porous-'washen a first sealing ring located betweenthe. inclined surface of said bushingvandfsaid Anon-porousv washer,` a1clamping washer having an inner surface inclined downwardlytowards-,said sheathed conductor, a'second sealing ring located betweensaid non-porous washerffand the. inclined rim. of; said sealing washer,and, afsealingl gasket located, between said clamping'washerrand the rimor saidy cuplikemember.,

f. 2. electric connection joints between an electrical apparatus housedwithin a casing l and an insulation-sheathed: llead-in wire, comprisinga cavityrdefining member registering ywith an opening imsaid Ieasingand. extending therein, said.

member having'anopen' `end facing the exterior ofthe casing', a.connector device `.carried by a Wall. ofrsaidrmember and-extending`inwardly ofthe cavity therein to connect withfsaid wire, meansito sealsaid' onenrend osaid member, the last-mentioned .meansv comprising insuperposed clamping relation; a first: non-porous. plastic washer, aclampingvwasher having an .inclined clamping surface, afrst deformable`sealing ring in; engagement with said. :inclined surface, a second.non-porous plastic washer in-'engagement With/said' clampingfwasher andlsaid iirst sealing-ring, asecond deformable sealing ring in engagement'with saidV second plastic .washer, a clamiiingl ring having an; inclinedsurface .in engagement. Withsaid` second sealing ring, means to'tightensaid clamping ring. tol clamp said rst noir-.porous washeragainst theopen end of said 1 memberfand to clamp said. sealing rings in grippingrelation with.. the Ysheathed conductor, .zand a tubular metal supportfastened to said casing and passing through said opening in said casingfor supporting said cavity-defining member within said casing, saidmember and said tubular support having cooperating spaced shoulders, athird deformable sealing ring located between said cooperating spacedshoulders, and means to clamp said third sealing ring between saidcooperating shoulders to seal said opening in said casing.

3. An electric connection joint between an electrical appaartus housedwithin a casing and an insulation-sheathed lead-in Wire, comprising acavity-defining member registering with an opening in said casing, saidmember having an open end facing the exterior of said casing, aconnector device carried by the bottom of said member to make connectionto said wire, means for hermetically sealing the said open end of saidmember the last-mentioned means including a first non-porous sealingwasher removably seated against the rim at the open end of said member,a rst metal clamping washer with an inclined inner rim, a rst deformablesealing ring surrounding said sheathed conductor between said conductorand said inclined rim, another metal clamping washer having an inclinedinner rim and surrounding said sheathed conductor, a second deformablesealing ring located between the inclined rim on said other metal washerand the sheath of said conductor, a non-porous plastic' washersandwiched between said sealing rings, means to clamp said rings andwashers together to deform said sealing rings into hermetic *grippingrelation with `saidinclined rims and with the sheath on said conductor,and a tubular metal `support passing through said opening in said casingand extending interiorly thereof to support said cavity-denng memberwithin the casing, said tubular support and said cavitydening memberhaving cooperating shoulders, a third deformable sealing ring locatedbetween said cooperating shoulders, and means to clamp said thirdsealing ring between said cooperating shoulders to hermetioally sealsaid opening in said casing. s

4. An electric connection joint for an electrical apparatus housedwithin a conductive casing which casing has an opening through which isto pass an insulation-sheathed lead-in conductor, comprising aninsulating 'member constituting a joint-enclosing cavity ofmoisture-proof insulation, said insulating member being closed at oneend and the opposite end being open and facing the exterior of saidcasing, a peripheral shoulder on said insulating member, a pair ofdeformable sealing rings surrounding said insulating member on oppositesides of said shoulder, said shoulder serving to hold said sealing ringsout of moisture conducting contact with each other, a pair of clampingelements to clamp said sealing rings against said shoulder, meansincluding a tubular metal member fastened to said casing andextending-through the casing opening to support one of said clampingelements and saidk insulating member interiorly of the casing, meansincluding said sealing rings to'hermetically seal said casing opening,and means to separately seal the said open end of said insulatingmember, the last-mentioned means including at least one deformablering.,

and a pair of cooperating clamping washers for causing saidlast-mentioned deformable ring to hermetically grip said sheathedconductor, one

of the last-mentioned clamping Washers being threaded `on toy acorresponding threaded extension on the said one of the first-mentionedclampingfelements. f

5. An electric connection joint for an electrical apparatus housedwithin a conductive casing which casing has an opening through which ist0 pass an insulation-sheathed lead-in conductor, comprising aninsulating member constituting a joint-enclosing cavity ofmoisture-proof insulation, said insulating member being closed at oneend'and the'opposite end being open and facing the exterior of saidcasing, a peripheral shoulder on said insulating-member, 'a pair ofdeformable sealing -rings surrounding said insulating member on oppositesides of said shoulder, said shoulder serving tohold said sealing ringsout of moisture conducting contact with each other, a pair of clampingelementsto clamp said sealing rings against said shoulder, meansincluding a tubular metal memberl fastened to said casing and extendingthrough the casing opening to support one of said clamping elements andsaid insulating member interiorly of the casing, means includinglsaidxsealing rings to hermetically seal said casing opening, and meansto separately seal the said open end of said insulating member, thelast-mentioned means lincluding a pair of deformable' sealing rings andcooperating inclined surface clamping washers for deforming said ringsinto gripping relation with said sheathed conductor,l a non-porousplastic washer sandwiched between the last-mentioned pair of sealingrings, one of the last-mentioned clamping washers being threaded on to acorresponding threaded extension onthe said one of the first mentionedclamping elements.

' FREDERICK G. STREET, JR.

References Cited 'in thefile of this patent '461,239 f AGreat BritainFeb. e, 1937

